<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>form</title>
</head>
<body>
    <!-- <form action="postGetParameter" method="post">
        post form表单方式处理请求 
        <input type="text" name="userId">
        <input type="text" name="classId">
        <input type="submit" value="提交">
    </form> -->
        <input type="text" id="userId"> 
        <input type="text" id="classId">
        <input type="button" value="提交" id="submit">
    <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
    <script>
        let userIdInput = document.querySelector('#userId');
        let classIdInput = document.querySelector('#classId');
        let button = document.querySelector('#submit');
        button.onclick = function(){
            $.ajax({
                type:'post',
                // url: 'postParaneter2',
                url:'postJson',
                contentType:'application/json',
                data: JSON.stringify({   //对于post请求ajax允许使用data请求对象
                    userId:userIdInput.value,
                    classId:classIdInput.value,
                }),
                success:function(body){
                    cosole.log(body);
                }
            });
        }    
    </script>
</body>
</html>